Dynamic fracture experiments of mortar using a high-speed loading apparatus driven by explosives

The dynamic fracture experiments of rock-like materials were carried out by using a high-speed loading apparatus driven by the electric detonator. The mortar specimens were loaded in splitting tension and/or bending. The dynamic fracture processes of the materials under high-speed loading were observed by the high-speed video camera system. The dynamic load was measured with a quartz type load cell. In the splitting tension experiment, cracks were firstly initiated near the center of the cross section of the specimen and the cracks propagated to the loading points. It is considered that the crack behavior is affected by the existence of compressive zones near the loading points. The crack behaviors agree with the results of the numerical simulation using the dynamic fracture process analysis code. The tensile strength of mortar under high-speed loading was as much as 100%∼140% greater than the static strength. In the bending experiments, three point bend specimens were used. The bending strength of mortar under high-speed loading was also as much as 120-180% greater than the static bending strength.